Cap for a motorcycle gas tank



FIG. 1 is a top perspective view;

FIG. 2 is a front elevational view, with the rear elevational view, the left side elevational view and the right side elevational view being mirror views thereof;

FIG. 3 is a top plan view; and,

FIG. 4 is a bottom plan view of my cap for a motorcycle gas tank. 

The ornamental design for a cap for a motorcycle gas tank, substantially as shown and described. 